<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        var socket;
        if(window.WebSocket){
            socket = new WebSocket("ws://localhost:2000/hello")
            //相当于channelRead0，ev可以收到服务端回送的消息
            socket.onmessage = function (ev) {
                var rt = document.getElementById("responseText");
                rt.value = rt.value + "\n" + ev.data
            }
            //相当于连接开启
            socket.onopen = function (ev) {
                var rt = document.getElementById("responseText");
                rt.value = "连接开启了。。。。";
            }
            //相当于连接关闭，感知到连接关闭
            socket.onclose = function (ev) {
                var rt = document.getElementById("responseText");
                rt.value = rt.value + "\n" + "连接关闭了。。。。";
            }
            //发送消息到服务器
            function send(message){
                if(!window.socket){
                    return;
                }
                if(socket.readyState == WebSocket.OPEN){
                    //发送消息
                    socket.send(message);
                }else{
                    alert("连接未打开");
                }
            }
        }else{
            alert("当前浏览器不支持websocket")
        }
    </script>
    <form onsubmit="return false">
        <textarea name="message" style="height: 300px; width: 300px;"></textarea>
        <input type="button" value="发送消息" onclick="send(this.form.message.value)" />
        <textarea id="responseText" style="height: 300px; width: 300px;"></textarea>
        <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''" />
    </form>
</body>
</html>